<template>
  <div class="container">
    <!-- 固定导航 -->
    <van-nav-bar
      fixed
      left-arrow
      @click-left="$router.back()"
      title="小智同学"
    ></van-nav-bar>

    <!-- 聊天主体区域 -->
    <div class="chat-list">
      <!-- 左侧是机器人小智 -->
      <div
        class="chat-item"
        v-for="(item, idx) in list"
        :key="idx"
        :class="item.name === 'xz' ? 'left' : 'right'"
      >
        <template v-if="item.name === 'xz'">
          <van-image
            fit="cover"
            round
            src="https://img.yzcdn.cn/vant/cat.jpeg"
          />
          <div class="chat-pao">{{ item.msg }}</div>
        </template>
        <!-- template可以将元素包裹起来，它只是逻辑上的容器，渲染时页面不会渲染它，不会产生DOM -->
        <!-- 右侧是当前用户 -->
        <template v-else>
          <div class="chat-pao">{{ item.msg }}</div>
          <van-image
            fit="cover"
            round
            :src="$store.state.user.userInfo.photo"
          />
        </template>
        <!-- $store.modules.user.userInfo.photo -->
      </div>
    </div>

    <!-- 对话区域 -->
    <div class="reply-container van-hairline--top">
      <van-field v-model.trim="word" placeholder="说点什么...">
        <span @click="send()" slot="button" style="font-size: 12px; color: #999"
          >提交</span
        >
      </van-field>
    </div>
  </div>
</template>

<script>
import { mapState } from 'vuex'
import io from 'socket.io-client'
export default {
  name: 'UserChat',
  data () {
    return {
      word: '',
      list: [ // 对话记录
        // { name: 'xz', msg: '你好，我是无所不知的小智同学！', timestamp: Date.now() },
        // { name: 'me', msg: '小智同学, 请问你知道你不知道什么吗？', timestamp: Date.now() },
        // { name: 'xz', msg: '我有点晕了', timestamp: Date.now() }
      ]
    }
  },
  created () {
    // 将socket挂载到vue对象上
    this.socket = io('http://localhost:8001', {
      query: {
        token: this.$store.state.tokenInfo.token
      },
      transports: ['websocket']
    })
    this.socket.on('connect', () => {
      this.list.push({
        name: 'xz',
        msg: '我上线了，你来找我玩吧',
        timestamp: Date.now()
      })
      this.$nextTick(() => { this.scrollToButtom() })
    })
    // 创建链接成功后进行监听 msg是从服务器回来的内容
    this.socket.on('message', (msg) => {
      // console.log(msg)
      msg.name = 'xz'
      this.list.push(msg)
      this.$nextTick(() => { this.scrollToButtom() })
    })
    // 创建时获取用户信息
    this.$store.dispatch('user/getProfile')
  },
  computed: {
    // 使用mapState获取命名空间的module中的数据
    ...mapState('user', ['userInfo'])
  },
  methods: {
    send () {
      const msg = this.word
      const timestamp = Date.now()
      this.socket.emit('message', {
        // name: 'me',
        msg,
        timestamp
      })
      this.list.push({
        name: 'me',
        msg,
        timestamp
      })
      this.$nextTick(() => { this.scrollToButtom() })
    },
    // 将滚动条设置到最底部
    scrollToButtom () {
      const dom = document.querySelector('.chat-list')
      dom.scrollTop = dom.scrollHeight
    }
  }
}
</script>

<style lang="less" scoped>
.container {
  height: 100%;
  width: 100%;
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  background: #fafafa;
  padding: 46px 0 50px 0;
  .chat-list {
    height: 100%;
    overflow-y: scroll;
    .chat-item {
      padding: 10px;
      .van-image {
        vertical-align: top;
        width: 40px;
        height: 40px;
      }
      .chat-pao {
        vertical-align: top;
        display: inline-block;
        min-width: 40px;
        max-width: 70%;
        min-height: 40px;
        line-height: 38px;
        border: 0.5px solid #c2d9ea;
        border-radius: 4px;
        position: relative;
        padding: 0 10px;
        background-color: #e0effb;
        word-break: break-all;
        font-size: 14px;
        color: #333;
        &::before {
          content: "";
          width: 10px;
          height: 10px;
          position: absolute;
          top: 12px;
          border-top: 0.5px solid #c2d9ea;
          border-right: 0.5px solid #c2d9ea;
          background: #e0effb;
        }
      }
    }
  }
}
.chat-item.right {
  text-align: right;
  .chat-pao {
    margin-left: 0;
    margin-right: 15px;
    &::before {
      right: -6px;
      transform: rotate(45deg);
    }
  }
}
.chat-item.left {
  text-align: left;
  .chat-pao {
    margin-left: 15px;
    margin-right: 0;
    &::before {
      left: -5px;
      transform: rotate(-135deg);
    }
  }
}
.reply-container {
  position: fixed;
  left: 0;
  bottom: 0;
  height: 44px;
  width: 100%;
  background: #f5f5f5;
  z-index: 9999;
}
</style>
